# Ultra light Thomas-Fermi Dark Matter

## TL;DR

This paper proposes a simple fermionic dark matter model based on the Thomas-Fermi approximation, which naturally predicts core-like density profiles and explains various galactic properties, especially with DM mass around 50 eV.

## Contribution

It introduces a hydrostatic equilibrium approach for fermionic dark matter that does not assume a fixed density profile, predicting core-like structures and matching galactic observations.

## Key findings

- Model explains bulk galactic properties and rotation curves.
- Dark matter mass around 50 eV fits observational data.
- Supermassive black holes naturally emerge in the framework.

## Abstract

We investigate the viability of a simple dark matter (DM) model consisting of a single fermion in the context of galactic dynamics. We use a consistent approach that does not presume a particular DM density profile but instead requires that the DM+baryon system is in hydrostatic equilibrium. Using a phenomenological baryon density profile, the model then predicts the DM distribution with a core like behavior close to the galactic center. The presence of supermassive black holes (SMBHs) in the center of large galaxies arises naturally in this framework. Using data from a set of large elliptical and spiral galaxies, and from a small set of dwarf galaxies, we find that the model can explain most of the bulk galactic properties, as well as some of the features observed in the rotation curves, provided the DM mass is in the $\mathcal{O}$(50 eV) range. More precise tests of the model require better modeling of the baryon profile and better control on the uncertainties in the data.